Carotenoids are naturally occurring pigments that are responsible for many of the vivid yellow, orange, and red colors observed in living organisms. Carotenoids are widely distributed in nature and perform a number of important biological functions, such as serving as light harvesting pigments in photosynthesis and protecting organisms from photo-oxidative damage.
In humans, carotenoids provide powerful antioxidant action, protecting the body from free radicals, which can develop as a result of normal metabolism as well as from exposure to pollution and other environmental hazards. Carotenoids also find use as natural pigments in foods and cosmetic products and in the nutraceutical/pharmaceutical industries as dietary precursors of vitamin A.
The global market for carotenoids is projected to top $1.2 billion US dollars by 2015. At the present time, close to 90% of the carotenoids on the market are produced by chemical synthesis. However, there is a growing interest in the development of processes for isolating carotenoids from sources in nature. It is well known that certain plants contain large amounts of carotenoids.
Palm oil is one of the richest sources of natural plant carotenoids known. Depending on its origin, palm oil can have between 500 and 7,000 mg/kg of carotenoids.
A number of processes for recovering carotenoids from palm oil or concentrating carotenoids are known. These methods include chemical modification of the oil and distillation, liquid-liquid extraction, and chromatography.
In one known process, palm oil is transesterified and then concentrated by extraction and distillation. In this process, palm oil is first transesterified with an alcoholic solvent, such as methanol forming fatty acid esters and glycerol. Once the reaction mixture is allowed to separate, the upper phase consisting of fatty acid ester with dissolved carotenoid is washed with a mixture of alcohol and water and then with water alone. The complete or partial removal of the fatty acid ester by distillation leaves a carotenoid concentrate. The distillation step is carried out in vacuo at temperatures of up to 150° C., which can take about 5 hours. In this process, the palm oil must be converted into a non-edible ester to aid in separation of the constituents of the palm oil. Thus, the processed palm oil material cannot be used in the preparation of food products. In addition, carotenoids readily decompose at the distillation temperature, which decreases the isolated yield and purity of the carotenoids left in the carotenoid concentrate.
Supercritical CO2 has also been used to isolate carotenoids from palm oil. In this process, palm oil is added to a high pressure extraction vessel and super critical carbon dioxide is passed through the vessel, extracting the carotenoids in the material in the process. The extract is collected and the carbon dioxide is then allowed to evaporate from the carotenoid extract. While this process produces carotenoid extracts in good purity, it is disadvantaged by the high cost of the process, the high operating pressures, and the very low solubility of carotenoids in super critical carbon dioxide.
In view of the foregoing limitations of existing isolation processes, there exists a need to develop an efficient and cost effective process for isolating carotenoids from liquids, such as palm oil, which does not modify the oil into non-edible compounds. In addition, there is also a need to develop a material for isolating carotenoids. The present disclosure addresses these needs and has related advantages.